Uninterruptible power supplies are used in many electrical and electronic systems to protect against loss or degradation of operation in the event of a utility power outage. Typical UPS systems include back-up batteries, standalone generators or other alternate power sources that may be brought on-line should an AC utility source fail to meet predetermined voltage or other performance criteria, e.g., under “brownout” and “blackout” conditions. In addition, UPS systems commonly include power conditioning circuits that are designed to reduce spikes, frequency variations, voltage excursions and other irregularities that are often present on AC utility lines. The back-up batteries provide power for computers and other electronic equipment when the main power is shut off so that the equipment is not damaged and so that data is not lost due to lack of continuous power to the equipment.
Typically, UPS systems are shipped with the battery disconnected to avoid unwanted use of the battery's power, and further to avoid injuries that can occur when current is being supplied to the electronic device. Thus, one shipping a UPS must take precautions to insure that the battery is disconnected, and the user of the system, upon receiving the UPS, must manually connect the battery to the UPS for use.
Batteries used in UPS systems are generally lead acid batteries manually connected to the UPS system. For example, the connections may involve manipulation of the leads or terminals of the battery during disconnection and reconnection of the battery in the UPS. To avoid injury to the user and damage to the system from a faulty battery, great care must be taken in connecting or replacing a battery in a UPS. This often requires that the system be powered down for a substantial amount of time so that the battery leads are appropriately connected.